|(coordinating) used to join terms when either one or the other or both is indicated: passports and/or other means of identification|
|usage Many people think that and/or is only acceptable in legal and commercial contexts. In other contexts, it is better to use or both: some alcoholics lose their jobs or their driving licences or both (not their jobs and/or their driving licences)|
Both or either of two options. For example, His use of copyrighted material shows that the writer is careless and/or dishonest. This idiom originated in legal terminology of the mid-1800s.